In polar and alpine regions worldwide, glacier retreat leads to the creation of new lakes in the newly-deglaciated proglacial terrain. However, little is known about the benthic inhabitants of these ‘new’ lakes, and how the communities therein compare with the pre-existing ‘old’ lakes.

In a new paper led by Jan Kollár and published in FEMS Microbiology Ecology, we used both traditional microscopy and amplicon sequencing to characterize the diatom and bacterial communities, respectively, of lakes on James Ross Island, Antarctic Peninsula. Both lake age, as well as lake physical and chemical characteristics, were then used to explain patterns in microbial community diversity and community structure. We found that microbial diversity in recent lakes, both for diatoms and bacteria, was approximately half that found in corresponding older lakes. Comparisons of these communities through ordinations and other statistical approaches revealed that recent and older communities form separate clusters and were significantly different from one another, with younger water bodies generally holding more ‘cryospheric specialists’ than older ones.

These results reveal that Antarctic lakes of different ages hold very different communities, and as more lakes are created in the future, it cannot be assumed that ‘more lakes’ will automatically equate to ‘more habitat’ for Antarctica freshwater residents.

Kollár J, Kopalová K, Kavan J, Vrbická K, Nývlt D, Nedbalová L, Stibal M, Kohler TJ (2023) Recently formed Antarctic lakes host less diverse benthic bacterial and diatom communities than their older counterparts. FEMS Microbiology Ecology 99:fiad08 doi: 10.1093/femsec/fiad087